For anyone heading for the city centre Aire in Reims. The clean air zone is now in effect. It covers some of the main arterial roads around the city centre including the easiest route to the aire. After a lot of messing about with Google maps I managed to set a route avoiding the zone only to find the only available route was blocked by police due to an ' incident'. Gave up and drove back out of the city. Note to self, avoid city centres 